A Potential Biocontrol Agent AC12AB for Managing Potato Common Scab.

Potato common scab (PCS) is an economically important disease worldwide. In this study we demonstrated the possible role of AC12AB in controlling PCS. Isolates of were obtained from CS infected tubers collected from Maine United States, which were confirmed by morphological and molecular analysis including 16S rRNA sequencing and RFLP analysis of amplified 16S-23S ITS. Pathogenicity assays related genes including , , and were also identified in all strains through PCR reaction. An antagonistic bacterial strain was isolated from soil in Punjab and identified as AC12AB based on 16S rRNA sequencing analysis. Methanolic extract of AC12AB contained azalomycin RS-22A which was confirmed by H and C-NMR, H/H-COSY, HMBC and HMQC techniques. AC12AB exhibited plant growth promotion attributes including Indole-3-acetic acid production with 17 μgmL titers, siderophores production, nitrogen fixation and phosphates solubilization potential. When tubers were inoculated with AC12AB, significant ( < 0.05) PCS disease reduction up to 90% was observed in greenhouse and field trials, respectively. Likewise, AC12AB significantly ( < 0.05) increased potato crop up to 26.8% in field trial. Therefore, plant growth promoting AC12AB could provide a dual benefit by decreasing PCS disease severity and increasing potato yield as an effective and inexpensive alternative strategy to manage this disease.